Oracle does not support a bit
datatype or any other type for true/false scenarios. Does one use the char(1)
field instead by using a specific letter to
I'm not an English native so I tend to use either 1 and 0 or '1' and '0'. Using 'Y' and 'N' make little sense if you aren't coding in English (yes, native language coding does exist). Using 'SI' and 'NO' or 'S' and 'N' doesn't look professional (just like naming variables with accented letters). Ones and zeroes, on the contrary, are pretty standard if you've coded in C, PHP or JavaScript. In any case, I always add the appropriate constraint to disallow any other character. Apart from subjective issues, I don't think there're noticeable performance gain in choosing CHAR or NUMBER. I like numbers a little more because I don't need to quote them :)
I agree it's a glaring omission but I've read seriously heated discussions on the subject in some Oracle forums; it's a kind of religious issue. Some claim that booleans belong to application data types and have no place in the database core. Honestly, I believe it's one of those We Have Been So Long Without It That We Had Better Say It Was On Purpose things.
By the way, MySQL has a BOOLEAN type but it's a synonym for TINYINT(1) so it eventually equals to 1 and 0; which is fine, because it also has the constants TRUE and FALSE that evaluate to 1 and 0.